Process for hydrogenation of dodecanedioic acid dinitrile

Abstract

A process for the catalytic hydrogenation of dodecanedioic acid dinitrile to the corresponding primary amine employing a hydrogenation catalyst which comprises 5-35% by weight of at least one of catalytically active cobalt and nickel as the active component supported on one or more oxides of aluminum, silicon, titanium and iron, wherein the specific surface area of the support material is 0.01-1.2m 2 /g., the pore volume is 0.05-0.4 ml./g., the annealing loss is less than 0.1% and the extractable alkalinity of the support is 0.08-20% by weight of the support. Sufficient alkali is present in the hydrogenation diluent to ensure that the desired alkali concentration remains on the catalyst surface, thereby extending the useful life of the catalyst.

What is claimed is: 
     
       1. A process for the catalytic hydrogenation of dodecanedioic acid dinitrile to the corresponding primary amine, which comprises: hydrogenating dodecanedioic acid dinitrile with a hydrogenation catalyst comprising 5 - 35% by weight of at least one of catalytically active cobalt and nickel as the active component supported on one or more of aluminum oxide, silicic acid or silica containing small amounts of the oxides of Na, Fe, Ca and Mg wherein the specific surface area of the support material is 0.1 - 0.8 m 2  /g., the pore volume thereof is 0.2 - 0.4 ml./g., the annealing loss is less than 0.1% and the extractable alkalinity of the support is 0.1 - 10% by weight of the support, said hydrogenation being conducted in the presence of a diluent and a sufficient amount of alkali to ensure that said alkali concentration remains on the surface of the hydrogenation catalyst.   
     
     
       2. A process according to claim 1, wherein the hydrogenation is conducted in the presence of a diluent and about 0.1 - 5% by weight, based on the hydrogenation mixture, of a hydroxide or carbonate of an alkali metal. 
     
     
       3. A process according to claim 2, wherein said hydroxide or carbonate is present in an amount of about 0.2 - 2%, based on the hydrogenation mixture. 
     
     
       4. A process according to claim 1, wherein the hydrogenation is conducted in the presence of about 1 - 5 moles of ammonia per mole of nitrile. 
     
     
       5. A process according to claim 4, wherein 2 - 4 moles of ammonia per mole of nitrile are employed. 
     
     
       6. A process according to claim 1, wherein the support material is an oxide of aluminum.